ORIGINAL PAPER Biological properties and enzymatic degradation studies of clindamycin-loaded PLA/HAp microspheres prepared from crocodile bones Juntima Pradid 1 • Wirunya Keawwatana 1 • Upsorn Boonyang 2 • Siree Tangbunsuk 1 Received: 1 February 2016 / Revised: 22 March 2017 / Accepted: 30 March 2017 Ó Springer-Verlag Berlin Heidelberg 2017 Abstract Polylactic acid (PLA)/hydroxyapatite (HAp) biocomposite microspheres with a specific core–shell structure for application as drug carriers were synthesised using an ultrasound field. In addition, the loading efficiency of clindamycin phos- phate increased when the HAp content was increased to 30%. The effect of HAp content on enzymatic degradation of PLA/HAp microspheres loaded with clin- damycin phosphate was that the degradation rate increased with increasing HAp content. Apatite formed on the surfaces of the PLA and PLA/HAp microsphere loading of clindamycin phosphate showed Ca and P peaks in energy-dispersive X-ray spectroscopy (EDX) data. In addition, the PLA and PLA/HAp microspheres loaded with clindamycin phosphate did not show any cytotoxicity against the human lung fibroblast MRC-5. Keywords Hydroxyapatite (HAp) Á Polylactic acid (PLA) Á Biological properties Á Enzymatic degradation Á Crocodile bones Á Clindamycin phosphate & Siree Tangbunsuk siree.t@ku.ac.th Juntima Pradid boom_foru@hotmail.com Wirunya Keawwatana fsciwyk@ku.ac.th Upsorn Boonyang upsorn.bo@wu.ac.th 1 Department of Chemistry, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand 2 MTRU, School of Science, Walailak University, Nakhon Si Thammarat 80161, Thailand 123 Polym. Bull. DOI 10.1007/s00289-017-2006-2